A company hires management trainees for entry level sales positions. Past experience indicates that only 20% will still be employed at the end of nine months. Assume the company recently hired six trainees.
I can't even get the mean
What is the standard deviation of the number of trainees that will still be employed at the end of nine months?
+6251 This isn't the greatest question in the world.
What they are trying to get at is that the number of trainees that are still employed is a binomial random variable, in this case with parameters \(n=6, p=0.2\)
You should know or can look up that the variance of a binomial random variable is given by
\(\sigma_{binomial} = n p (1-p) \\ \mbox{so here we have}\\ \sigma = 6 (0.2)(0.8) = 0.96\)
+6251 This isn't the greatest question in the world.
What they are trying to get at is that the number of trainees that are still employed is a binomial random variable, in this case with parameters \(n=6, p=0.2\)
You should know or can look up that the variance of a binomial random variable is given by
\(\sigma_{binomial} = n p (1-p) \\ \mbox{so here we have}\\ \sigma = 6 (0.2)(0.8) = 0.96\)
